Soy protein and animal protein give similar muscle gains
What it found
In nine studies of 266 people doing resistance training, soy protein supplements produced similar gains in muscle mass and strength as animal proteins like whey, beef, milk or dairy.
What they found
Studies in people
Strength gains
Both whey and soy protein supplements led to significant increases in strength, with no difference between the two groups for bench press or squat.
Muscle mass change
Whey or soy alone had no significant effect on lean body mass change, and there was no difference between the groups.
Other proteins vs soy
Strength and lean body mass both increased significantly in the soy group and in the group using other proteins, but there were no differences between them.
What the authors conclude
“The results of this meta-analysis indicate that soy protein supplementation produces similar gains in strength and LBM in response to RET as whey protein.”
Also in their conclusions
- They conclude that soy protein supplementation produces similar gains in strength and lean body mass in response to resistance exercise training as whey protein.
How it was done
Scientists wanted to know whether the type of protein supplement affects strength and lean body mass over the long term, since short-term studies suggest whey may stimulate muscle protein synthesis more than soy.
They combined nine studies with 266 participants who did resistance exercise training for at least six weeks. Five studies compared whey with soy protein, and four compared soy with other proteins such as beef, milk or dairy protein.
What it can’t tell you
- We summarised it from the abstract only.
- This analysis combined results from different studies, so it cannot show how any one person would respond to soy or animal protein.
- It only looked at healthy people doing resistance training, so the results may not apply to other groups.
The paper
- Title
- No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise
- Type
- Meta-analysis
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Messina M, Lynch H, Dickinson JM, Reed KE (2018). No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise. International journal of sport nutrition and exercise metabolism. doi:10.1123/ijsnem.2018-0071PubMed 29722584DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error